Riso Kagaku Corporation

Hiroyuki Ogawa

Toshihiro Endo

Osamu Matsumoto

Teruaki Ohkawa

Hajime Tsunoda

Sadanao Okuda

Yasuo Yamamoto

Akiko Hayashi

Kokoro Kinoe

Yuki Urano

Hiromichi Yamada

Kazuhiro Higashi

Hideaki Takayama

Masami Shinozaki

Kazunori Ohashi

A white ink for an inkjet, comprising a silica, a resin emulsion, and water, wherein an amount of the resin emulsion, reported as a mass ratio relative to a value of 1 for the silica, is within a range from 0.10 to 0.45.

White ink for inkjet

An ink for inkjet printing including a pigment, a water-dispersible resin, water, and a water-soluble organic solvent, wherein the water-dispersible resin is an anionic resin having a film elongation of 400-1,000%, a tensile strength of 20 to 50 N/mmand an absolute value for the zeta potential (mV) of 40 or greater, the amount of the anionic resin, reported as a weight ratio relative to the pigment, is within a range from (0.5 to 2.5)/1, and the surface tension of the ink is within a range from 30 to 50 mN/m.

Ink for inkjet printing

An ink for inkjet recording containing a vehicle, coloring agents dispersed therein, and a dispersing agent for the coloring agents as required, is provided. The vehicle contains at least a first solvent component and a second solvent component. The first solvent component has the lowest boiling point among the components in the ink, and has a higher viscosity than the ink. The second solvent component has a higher boiling point than the first one. The boiling point of the first solvent component is preferably 280 degree C. or below, and the content thereof is preferably 10 to 80% by weight based on the total weight of the ink. Even when the ink is printed on non-coated papers, the vehicle penetrates little in the thickness direction and bleeds little in the horizontal direction. Clogging in the nozzles can be prevented effectively using the ink even when it has been left in an open atmosphere for a long time.

Ink for inkjet recording

To provide a non-aqueous ink composition which is small in generation of strike through or smear marks and free from the problem of clogging of the nozzle. A non-aqueous ink composition includes solvent, dispersant and coloring material of pigment or dye. The solvent contains therein at least not smaller than 10% by weight non-polar organic solvent which is not higher than 260&#xb0; C. in 50% running point and at least not smaller than 20% by weight polar organic solvent which is not lower than 300&#xb0; C. in 50% running point.

Non-aqueous ink composition

A water-in-oil (W/O) emulsion ink for stencil printing is provided which is prevented from pigment aggregation and thus excellent in ink fixability, high in printing density and less declining in printing density even after printing many sheets. The emulsion ink has a ratio by volume of the water phase to liquid components of the oil phase (i.e., volume of water phase/volume of the liquid components of oil phase) in a range of 1.0 to 3.5, preferably 1.0 to 3.0 at 23&deg; C. The liquid components of the oil phase may be composed of a resin, a solvent and a surfactant. The oil phase can contain a pigment at a ratio by volume of 0.19 or less to the total volume of the oil phase. The pigment preferably has an average particle size of 0.02 to 1.5 (&mgr;m). The water phase preferably has an average particle size of 0.1 to 1.0 (&mgr;m). The ink is suitable for containing particles of organic pigments with non-uniform shapes and a large average particle size like copper phthalocyanine blue and diaxazine violet.

Emulsion ink for stencil printing

Emulsion ink for stencil printing and its use

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Ibaraki-ken, Japan

Hiroyuki Ogawa